When cattle are slaughtered, they are initially stunned or killed and blood is drained from their carcasses. The carcass is subsequently skinned and cut into halves. These halves are referred to as sides of beef. The sides of beef are then cooled and graded by a government inspector in preparation for sale.
Between the time that the carcass is skinned and the time that it is inspected, the carcass must be stored and refrigerated to remove body heat. During this chilling period, if not shrouded the carcass tends to lose excessive amounts of natural moisture. This natural moisture enhances the quality of the meat and adds to the weight of a carcass. In order to avoid excessive water loss, it has become the custom to cover the carcass with a piece of fabric usually called a shroud. The shroud, which is typically soaked in brine, tightly fixes against the outer surface or warm fat of the carcass.
These brine-soaked shrouds serve several purposes. Of course, one purpose is to retain the natural moisture within the carcass. The brine also acts to bleach and disinfect the surface of the carcass, making it more appealing. Since the carcass shroud tightly stretches over the surface of the carcass, it smoothes the warm fat, making it more appealing to the eye and causing the carcass to receive a better grade from the government inspector. These shrouds have been made from various fabrics. These include cotton, rayon, ramie, polyethylene terephthalate (PET), as well as plastic films bonded to cotton or the like.
The natural fiber shrouds have several disadvantages. First of all, they must be soaked and applied wet or they will stick to the surface of the carcass and pull away fat when removed. Cotton shrouds, even when applied wet, tend to stick to the surface of the carcass leaving textile fibers behind. The cotton fibers remaining on the carcass are a source of contamination which can result in reduced storage life for the meat.
These shrouds are also very expensive, and accordingly, are not disposable. They must be reused repeatedly. This presents somewhat of a dilemma. Used shrouds are contaminated with microorganisms. Because of the quality of these shrouds, they will not withstand the thorough washing and sterilization required to kill the microorganisms growing on the shrouds. Accordingly, the reuse of natural fiber or cotton shrouds tends to carry microorganisms to the surface of the carcass. In the past, this problem has been solved by adding an antibiotic to the shroud or by applying the antibiotic to the carcass prior to shrouding. Excessive bacterial contamination results in reduced storage life for the meat.
Goeser U.S. Pat. No. 2,697,664 discloses a modified cotton shroud wherein one side of the cotton shroud is coated with a perforated plastic film. The shroud was stated to have a water vapor permeability of from 0.25 to 2.75 grams per 50 cm.sup.2 per 24 hours at room temperature and such a shroud prevents surface water from passing through the shroud. Also, this shroud contained body heat and increased the time for lowering to a safe level the interior body temperature of the carcass. In other words, the film prevents escape of evaporative water and, thus, the cooling rate of the carcass is reduced. Other examples of employing films with pin holes or perforations to provide a moisture-vapor permeability or transmission rate between 0.25 and 2.75 grams per 50 cm.sup.2 per 24 hours at room temperature and 100% relative humidity are disclosed in U.S. Pat. No. 2,699,396 in combination with an absorptive layer of fibrous material.
U.S. Pat. No. 3,124,468 discloses the application of a plastic coated cotton or cellulosic fiber shroud in a dry state onto a carcass. The fibrous side is applied against the carcass. This method is totally unsatisfactory because a dry cellulosic, fibrous fabric applied to the warm carcass fat will stick to the carcass and pull fat from the carcass when it is eventually separated from the chilled carcass.
A recent development, as reported in Kocay U.S. Pat. No. 3,741,260, is the use of a non-swelling, non-wicking meat shroud of high tenacity polyethylene terephthalate (PET) staple fibers. These shrouds are unacceptable because they do not sufficiently adhere to the surface of the carcass. As water seeps from the carcass, it pushes the PET material away from the carcass. A shroud which does not sufficiently adhere to the surface of a carcass does not act to smooth the outer fat layer of the carcass. In fact, a PET shroud will loosen from the carcass during chilling. Thus, when the shroud is removed, the carcass does not have a smooth appearance which results in a downgrading of the beef.
Thus, until now, no one has produced a low cost effective carcass shroud.